Treatment Disparities Persist for Women vs Men Following MI

More investigation is needed on the treatment and outcome disparities that persist between younger men and women in the year after a myocardial infarction (MI), or heart attack, according to new data on 38,071 heart attack survivors living in Ontario, Canada.

The patients in this observational analysis were all aged 18 to 55 years and hospitalized between April 1, 2009, and March 31, 2019, in Ontario. Differences in cardiovascular hospital readmission rates, all-cause hospital readmission rates, heart disease/cardiac risk factors, treatment, angiographic findings, and revascularization rates were investigated between women and men.

Data were supplied by ICES, formerly known as the Institute for Clinical Evaluative Sciences, and several other databases provided information on patient comorbidities, hospital admission status, physician follow-up, neighborhood income information, and patient vital status. Acute MI (AMI) diagnosis was identified with International Classification of Diseases, 10th revision, Canada codes.

Data were supplied by ICES, formerly known as the Institute for Clinical Evaluative Sciences, and several other databases provided information on patient comorbidities, hospital admission status, physician follow-up, neighborhood income information, and patient vital status. Acute MI (AMI) diagnosis was identified with International Classification of Diseases, 10th revision, Canada codes.

Findings were published online today with Canadian Journal of Cardiology.

“Vigorous efforts to address these treatment disparities with public education campaigns and calls to action have been aimed at the cardiology community,” the study investigators wrote. “Despite these efforts, there are concerns that the improvement in clinical outcomes experienced after AMI hospitalization is not being realized among younger women.”

Far fewer women (21.2%) than men made up the overall patient population, but among these women, diabetes prevalence rose steadily throughout the study period, from 24.8% in 2009 to 34.9% (Ptrend < .001) in 2018 compared with 18% and 22%, respectively, in men. The smoking rate dropped in both, to 41.7% from 53.2% among the women and to 43.3% from 52.7% in the men.

Additionally, normal coronary anatomy and nonobstructive disease were more common in women than men, at 5.8% vs 1.7% and 22.8% vs 9.3% (both P < .001), respectively. Further, there was a very high overall rate of coronary angiography (95.9%) in this study, but coronary revascularization via percutaneous coronary intervention (PCI) and surgery occurred at lower rates in women than men:

• PCI: 61.9% vs 78.8% (P < .001)
• Surgery: 4.1% vs 6.0% (P < .001)

Also, fewer woman than men received coronary angiography during hospitalization: 93.5% vs 96.6%.

However, both the primary composite end point of 1-year all-cause mortality or readmission for unstable angina, AMI, heart failure, or stroke and all-cause readmission on its own were higher among the women in this study, at 10.0% vs 7.9% and 25.8% vs 21.1%, respectively . For the composite end point, women had an 11% greater risk (HR, 1.11; P = .02) and for all-cause readmission, a 34% greater risk (HR, 1.34; P < .0001). But 1-year mortality was close to equal, at 2.9% among the women and 2.8% among the men (adjusted HR, 1.08; 95% CI, 0.88-1.20; P = .70).

Cardiac risk factors evaluated at baseline were diabetes, hypertension, dyslipidemia, current smoker, and former smoker, and of these, diabetes and hypertension were more common in the female study participants (both P < .001). Weighted, however, 4 of the 5 (former smoker being the exception), were more common among the women.

Of the 9 comorbidities observed at baseline (previous MI, previous PCI, previous coronary artery bypass graft, heart failure, renal disease, chronic obstructive pulmonary disease, cancer, peripheral vascular disease, cerebrovascular disease), only PCI was more common among the men (P < .001). Left-ventricular ejection fraction of 50% or more was more common in the women and ejection fractions of 35% to 49% and 20% to 34% were more common among the men (both P < .001).

An accompanying editorial noted that “This important analysis by Madan et al presents us with both good news and bad news. Although coronary angiography is now routinely offered to almost 96% of patients with AMI, small but significantly lower rates were observed in women. And although adjusted mortality rates at 1 year do not differ by sex, crude mortality rates continue to demonstrate higher rates in women, apparently driven by higher levels of comorbid conditions.”

The authors of the editorial suggest more focus on factors beyond comorbidities, since hospital readmission rates among women remain higher for cardiovascular and noncardiovascular causes, and the study authors suggest “the need for ongoing intensive primary prevention strategies directed at younger women.”

Reference

Madan M, Qiu F, Sud M, et al. Clinical outcomes in younger women hospitalized with an acute myocardial infarction: a contemporary population-level analysis. Can J Cardiol. Published online October 5, 2022. doi:10.1016/j.cjca.2022.06.023